Intercooled cooled cooling integrated air cycle machine

ABSTRACT

An intercooled cooling system for a gas turbine engine is provided. The intercooled cooling system includes cooling stages in fluid communication with an air stream utilized for cooling. A first cooling stage is fluidly coupled to a bleed port of the gas turbine engine to receive and cool bleed air with the air stream to produce a cool bleed air. The intercooled cooling system includes a pump fluidly coupled to the first cooling stage to receive and increase a pressure of the cool bleed air to produce a pressurized cool bleed air. A second cooling stage is fluidly coupled to the pump to receive and cool the pressurized cool bleed air to produce an intercooled cooling air. The intercooled cooling system includes an air cycle machine in fluid communication to outputs of the cooling stages to selectively receive the cool bleed air or the intercooled cooling air.

BACKGROUND

This present disclosure relates to a gas turbine engine, and moreparticularly to improvements in providing cooling air from a compressorsection to a turbine section in a gas turbine engine.

Gas turbine engines are known and typically include a fan delivering airinto a bypass duct as propulsion air. Further, the fan delivers air intoa compressor section where it is compressed. The compressed air passesinto a combustion section where it is mixed with fuel and ignited.Products of this combustion pass downstream over turbine rotors drivingthem to rotate.

It is known to provide cooling air from the compressor to the turbinesection to lower the operating temperatures in the turbine section andimprove overall engine operation. Typically, air from the highcompressor discharge has been tapped, passed through a heat exchanger,which may sit in the bypass duct and then delivered into the turbinesection. The air from the downstream most end of the compressor sectionis at elevated temperatures.

Running the operating temperatures in the turbine section at hightemperatures provides efficiency gains in the gas turbine engine;however, the high temperatures are exceeding material limits and aredriving the need for improved cooling air. That is, conventional coolingair methods fail to provide cooling air at sufficient pressure to beintroduced to the highest pressure places of the gas turbine engine andat cool enough temperature to reduce key component temperatures.

BRIEF DESCRIPTION

In accordance with one or more embodiments, an intercooled coolingsystem for a gas turbine engine is provided. The intercooled coolingsystem includes a plurality of cooling stages in fluid communicationwith an air stream utilized by the plurality of cooling stages forcooling. A first cooling stage of the plurality of cooling stages isfluidly coupled to a bleed port of a compressor of the gas turbineengine to receive and cool bleed air with the air stream to produce acool bleed air. The intercooled cooling system includes a pump fluidlycoupled to the first cooling stage to receive and increase a pressure ofthe cool bleed air to produce a pressurized cool bleed air. A secondcooling stage of the plurality of cooling stages is fluidly coupled tothe pump to receive and cool the pressurized cool bleed air to producean intercooled cooling air. The intercooled cooling system includes anair cycle machine in fluid communication to outputs of the first andsecond cooling stages to selectively receive at least a portion of thecool bleed air or at least a portion of the intercooled cooling air.

In accordance with another embodiment or the intercooled cooling systemembodiment above, the air cycle machine can comprise a turbineconfigured to receive and extract work from the portion of the coolbleed air or the portion of the intercooled cooling air.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the turbine can produce byproduct of cold airfrom the extraction of work from the portion of the cool bleed air orthe portion of the intercooled cooling air.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the byproduct of cold air can be provided as acooling sink for an environmental control system.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the air cycle machine can comprise a generatorcoupled to receive pneumatic power from the turbine.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the generator can provide electricity based onthe pneumatic power to one or more of an electric heater, an auxiliarysystem, a motor drive, and an aircraft system.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the intercooled cooled cooling air system cancomprise a first valve configured to selectively provide the cool bleedair to the air cycle machine; and a second valve configured toselectively provide the intercooled cooling air to the air cyclemachine.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the bleed port can comprise a port at a lowpressure location of the compressor or a port at a mid-pressure locationof the compressor.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the plurality of cooling stages can beconfigured in a main bypass of the gas turbine engine to receive the airstream.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the plurality of cooling stages can beconfigured on a duct wall, and wherein the air stream comprises acombination of streams.

In accordance with another embodiment or any of the intercooled coolingsystem embodiments above, the intercooled cooling air can be outputtedby the second cooling stage is mixed with second bleed air sourced froma second bleed port of the compressor.

In accordance with one or more embodiments, a gas turbine engine isprovided. The gas turbine engine comprises a compressor section; acombustor section; a turbine section; and an intercooled cooling systemfor a gas turbine engine. The intercooled cooling system comprises aplurality of cooling stages in fluid communication with an air streamutilized by the plurality of cooling stages for cooling. A first coolingstage of the plurality of cooling stages is fluidly coupled to a bleedport of a compressor of the gas turbine engine to receive and cool bleedair with the air stream to produce a cool bleed air. The intercooledcooling system comprises a pump fluidly coupled to the first coolingstage to receive and increase a pressure of the cool bleed air toproduce a pressurized cool bleed air. A second cooling stage of theplurality of cooling stages is fluidly coupled to the pump to receiveand cool the pressurized cool bleed air to produce an intercooledcooling air. The intercooled cooling system comprises an air cyclemachine in fluid communication to outputs of the first and secondcooling stages to selectively receive at least a portion of the coolbleed air or at least a portion of the intercooled cooling air.

In accordance with another embodiment or the gas turbine engineembodiment above, the air cycle machine can comprise a turbineconfigured to receive and extract work from the portion of the coolbleed air or the portion of the intercooled cooling air.

In accordance with another embodiment or any of the gas turbine engineembodiments above, the turbine can produce a byproduct of cold air fromthe extraction of work from the portion of the cool bleed air or theportion of the intercooled cooling air.

In accordance with another embodiment or any of the gas turbine engineembodiments above, the byproduct of cold air can be provided as acooling sink for an environmental control system.

In accordance with another embodiment or any of the gas turbine engineembodiments above, the air cycle machine can comprise a generatorcoupled to receive pneumatic power from the turbine.

In accordance with another embodiment or any of the gas turbine engineembodiments above, the generator can provide electricity based on thepneumatic power to one or more of an electric heater, an auxiliarysystem, a motor drive, and an aircraft system.

In accordance with one or more embodiments, a method of providing bleedair to an air cycle machine is provided. The method comprises cooling ableed air flow in the first cooling stage to produce a cooled bleed airflow; increasing a pressure of the cooled bleed air flow in the pump toproduce a pressurized cooled bleed air flow; cooling the pressurizedcooled bleed air flow in the first second exchanger to produce anintercooled cooling air; and selectively receiving at least a portion ofthe cool bleed air or at least a portion of the intercooled cooling airby the air cycle machine that is in fluid communication with outputs ofthe first and second cooling stages.

In accordance with another embodiment or any of the method embodimentsabove, the method can comprise extracting work from the portion of thecool bleed air or the portion of the intercooled cooling air by aturbine of the air cycle machine to produce pneumatic power; andgenerating electricity by a generator coupled to the turbine based onthe pneumatic power.

In accordance with another embodiment or any of the method embodimentsabove, the generator can provide electricity based on the pneumaticpower to one or more of an electric heater, an auxiliary system, a motordrive, and an aircraft system.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 schematically shows an embodiment of a gas turbine engine.

FIG. 2 is an intercooled cooled cooling air system in accordance with anembodiment; and

FIG. 3 is an intercooled cooled cooling air system with an integratedair cycle machine in accordance with another embodiment.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool turbofan thatgenerally incorporates a fan section 22, a compressor section 24, acombustor section 26 and a turbine section 28. Alternative engines mightinclude an augmenter section (not shown) among other systems orfeatures. The fan section 22 drives air along a bypass flow path B in abypass duct, while the compressor section 24 drives air along a coreflow path C for compression and communication into the combustor section26 then expansion through the turbine section 28. Although depicted as atwo-spool turbofan gas turbine engine in the disclosed non-limitingembodiment, it should be understood that the concepts described hereinare not limited to use with two-spool turbofans as the teachings may beapplied to other types of turbine engines including three-spoolarchitectures.

The exemplary engine 20 generally includes a low speed spool 30 and ahigh speed spool 32 mounted for rotation about an engine centrallongitudinal axis A relative to an engine static structure 36 viaseveral bearing systems 38. It should be understood that various bearingsystems 38 at various locations may alternatively or additionally beprovided, and the location of bearing systems 38 may be varied asappropriate to the application.

The low speed spool 30 generally includes an inner shaft 40 thatinterconnects a fan 42, a low pressure compressor 44 and a low pressureturbine 46. The inner shaft 40 is connected to the fan 42 through aspeed change mechanism, which in exemplary gas turbine engine 20 isillustrated as a geared architecture 48 to drive the fan 42 at a lowerspeed than the low speed spool 30. The high speed spool 32 includes anouter shaft 50 that interconnects a high pressure compressor 52 and highpressure turbine 54. A combustor 56 is arranged in exemplary gas turbine20 between the high pressure compressor 52 and the high pressure turbine54. An engine static structure 36 is arranged generally between the highpressure turbine 54 and the low pressure turbine 46. The engine staticstructure 36 further supports bearing systems 38 in the turbine section28. The inner shaft 40 and the outer shaft 50 are concentric and rotatevia bearing systems 38 about the engine central longitudinal axis Awhich is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor 44 thenthe high pressure compressor 52, mixed and burned with fuel in thecombustor 56, then expanded over the high pressure turbine 54 and lowpressure turbine 46. The turbines 46, 54 rotationally drive therespective low speed spool 30 and high speed spool 32 in response to theexpansion. It will be appreciated that each of the positions of the fansection 22, compressor section 24, combustor section 26, turbine section28, and fan drive gear system 48 may be varied. For example, gear system48 may be located aft of combustor section 26 or even aft of turbinesection 28, and fan section 22 may be positioned forward or aft of thelocation of gear system 48.

The engine 20 in one example is a high-bypass geared aircraft engine. Ina further example, the engine 20 bypass ratio is greater than about six(6), with an example embodiment being greater than about ten (10), thegeared architecture 48 is an epicyclic gear train, such as a planetarygear system or other gear system, with a gear reduction ratio of greaterthan about 2.3 and the low pressure turbine 46 has a pressure ratio thatis greater than about five. In one disclosed embodiment, the engine 20bypass ratio is greater than about ten (10:1), the fan diameter issignificantly larger than that of the low pressure compressor 44, andthe low pressure turbine 46 has a pressure ratio that is greater thanabout five 5:1. Low pressure turbine 46 pressure ratio is pressuremeasured prior to inlet of low pressure turbine 46 as related to thepressure at the outlet of the low pressure turbine 46 prior to anexhaust nozzle. The geared architecture 48 may be an epicycle geartrain, such as a planetary gear system or other gear system, with a gearreduction ratio of greater than about 2.3:1. It should be understood,however, that the above parameters are only exemplary of one embodimentof a geared architecture engine and that the present disclosure isapplicable to other gas turbine engines including direct driveturbofans.

A significant amount of thrust is provided by the bypass flow B due tothe high bypass ratio. The fan section 22 of the engine 20 is designedfor a particular flight condition—typically cruise at about 0.8 Mach andabout 35,000 feet (10,688 meters). The flight condition of 0.8 Mach and35,000 ft (10,688 meters), with the engine at its best fuelconsumption—also known as “bucket cruise Thrust Specific FuelConsumption (‘TSFC’)”—is the industry standard parameter of lbm of fuelbeing burned divided by lbf of thrust the engine produces at thatminimum point. “Low fan pressure ratio” is the pressure ratio across thefan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The lowfan pressure ratio as disclosed herein according to one non-limitingembodiment is less than about 1.45. “Low corrected fan tip speed” is theactual fan tip speed in ft/sec divided by an industry standardtemperature correction of [(Tram ° R)/(518.7° R)]0.5. The “Low correctedfan tip speed” as disclosed herein according to one non-limitingembodiment is less than about 1150 ft/second (350.5 m/sec).

Turning now to FIG. 2, an intercooled cooled cooling air system 100 isprovided in accordance with an embodiment. In general, the intercooledcooled cooling air system 100 comprises a staged cooling arrangementcoupled to an air cycle machine. The stages cooling arrangement cancomprise one or more heat exchangers for each stage. In operation, bleedair from a first compressor is put through a first stage of the stagedcooling arrangement (e.g., a first heat exchanger or set of heatexchangers). The flow is collected and run through a second compressorto pump it up. The discharge of the second compressor is then runthrough a second stage of the staged cooling arrangement (e.g., a secondheat exchanger or set of heat exchangers) before being delivered asintercooled cooled cooling air. The air cycle machine can selectivelyreceive a percentage or portion of the cooling air from the stagedcooling arrangement (e.g., bleed air running through the inter-cooledloop). The air cycle machine can utilize the received cooling air toprovide pneumatic power to an accessory with a byproduct being cool/coldair.

The intercooled cooled cooling air system 100 is in fluid communicationwith bleed air of a gas turbine engine 20, which is illustratedschematically in FIG. 2. A non-limiting gas turbine engine 20 isdescribed and illustrated in FIG. 1. Components of the gas turbineengine 20 that are similar to the gas turbine engine 20 of FIG. 1 havebeen reused for ease of explanation, by using the same identifiers, andare not re-introduced. As shown in FIG. 2, components of theenvironmental control system 100 comprise a pump 105 and at least oneheat exchanger as the staged cooling arrangement. In one non-limitingembodiment, the at least one heat exchanger may comprise a first heatexchanger 110 (a first cooling stage) and a second heat exchanger 115 (asecond cooling stage). Components of the environmental control system100 may also comprise a first port 145, a valve 150, a second port 165,a valve 170, a demarcation or mixing chamber 180, a valve 182, a port184, an air cycle machine 190, a valve 195, and a valve 196.

As shown in FIG. 2, the pump 105, the first heat exchanger 110, and thesecond heat exchanger 115 are in fluid communication with bleed air ofthe gas turbine engine 20. Bleed air (e.g., a first bleed air flow) canbe extracted from a first port 145 of the compressor section 24 of thegas turbine engine 20, as regulated by a valve 150. Bleed air (e.g., asecond bleed air flow) can also be extracted from a second port 165 ofthe compressor section 24 of the gas turbine engine 20, as regulated bya valve 170. These portions can be mixed, as noted by demarcation 180,before being sent through a valve 182 to a third port 184 of the turbinesection 28 of the gas turbine engine 20. Further, the air cycle machine190 is in fluid communication with outputs of the first heat exchanger110 and the second heat exchanger 115, as respectively regulated by thevalve 195 and the valve 196.

A heat exchanger (e.g., the first heat exchanger 110 and a second heatexchanger 115) is a device built for efficient heat transfer from onemedium to another. Examples of heat exchangers include circular, doublepipe, shell and tube, plate, plate and shell, adiabatic wheel, platefin, pillow plate, and fluid heat exchangers.

The pump 105 (along with the compressor section 24) is a mechanicaldevice built to raise a pressure of a medium. The compressor section 24,particularly, receives a medium (e.g., fresh atmospheric air) that flowsthrough the compressor, which brings the medium to higher pressure. Thepump 105 can raise the pressure of air bled from the compressor section24. Examples of pumps and compressors include turbines, impellers,centrifugal compressors, diagonal or mixed-flow compressors, axial-flowimpellers, reciprocating devices, ionic liquid piston devices, rotaryscrew compressors, rotary vane compressors, scroll compressors,diaphragm compressors, air bubble compressors, etc. Further, the pump105 can be driven by a motor or a medium. In a non-limiting embodiment,the pump 105 can be an impeller.

The combustor section 26 can comprise a diffuser and a combustor toenable combustion of the medium. The combustor is a component or area ofthe gas turbine engine 20 where combustion takes place. Combustioncomprises when energy is added to a medium received from the compressorsection 24, which is at the higher pressure, by spraying fuel into themedium and igniting the fuel (so the combustion generates ahigh-temperature flow of the medium). The diffuser is a component thatslows the medium from the compressor section 24 (e.g., the high speed,highly compressed air) to a velocity optimal for combustion.

The turbine section 28 extracts energy from a medium flow. For example,the turbine of the turbine section 28 is a rotary mechanical device thatexpands a medium received from the diffuser and combustor of thecombustor section 26 down to an exhaust pressure to produce thrust.

Bleed ports are apertures that allow for a medium to be bled from thecompressor section 24 (i.e., a compressor stage of the gas turbineengine 20, upstream of the combustor section 26) and may be locatedanywhere along the compressor section 24 (e.g., anywhere along the lowpressure compressor 44 and the high pressure compressor 52 of FIG. 1). Atemperature, a humidity, and a pressure of a bleed medium, also referredto as bleed air, varies depending upon a compressor stage and arevolutions per minute of the gas turbine engine 20. In a non-limitingembodiment, a plurality of bleed ports are represented by the first port145 and the second port 165. The first port 145 can be a low pressurebleed port that is located towards an intake side of the compressor(e.g., the low pressure compressor 44) of the compressor section 24,where the pressure of the air is at or near atmospheric pressure. Thesecond port 165 can be a high pressure bleed port that is locatedtowards an exhaust side of the compressor (e.g., the high pressurecompressor 52) of the compressor section 24, where the pressure of theair is at or near combustion pressure. The first port 145 can also belocated at a mid-compressor bleed location, where the pressure of theair is between atmospheric pressure and combustion pressure. In contrastto the first port 145 and the second port 165, the third port 184 is anaperture that allows for a medium to be supplied to the gas turbineengine 20. In a non-limiting embodiment, the third port 184 is shown asbeing located at or near an intake of the turbine section 28 (downstreamof the combustor section 26).

The valves 150, 170, 182, 195, and 196 are devices that regulate,direct, and/or control a flow of a medium by opening, closing, orpartially obstructing various passageways within the tubes, pipes, etc.of the intercooled cooled cooling air system 100. Valves 150, 170, 182,195, and 196 can be operated by actuators, such that flow rates of themedium in any portion of the intercooled cooled cooling air system 100can be regulated to a desired value. Examples of valves 150, 170, 182,195, and 196 include a flow regulation device or a mass flow valve. In anon-limiting embodiment, the valve 195 and the valve 196 can be operatedby a control system coupled to the intercooled cooled cooling air system100 to selectively regulate percentages or portions of bleed air flowingto the air cycle machine 190 (by controlling the actuators that managethe operations of the valve 195 and the valve 196). In anothernon-limiting embodiment, the valve 150 can be a shut off or modulatedvalve and can require a check; the valve 195 can divert flow after afirst cooling stage as a cooling source or direct cool air supply; thevalve 196 can split flow between air cycle machine or some other bleeddemand; the valve 170 can modulate uncooled “mixing” bleed to cooledcooling air; and the valve 182 can control cooled cooling air flow ordirect where the flow is going.

A mixing point is a location within the intercooled cooled cooling airsystem 100 where multiple medium and/or multiple medium flows arecombined. In a non-limiting embodiment, the demarcation 180 marks amixing point between the first bleed air flow and the second bleed airflow.

The air cycle machine 190 is a mechanical device that includescomponents for performing thermodynamic work on the medium (e.g.,extracts or works on the medium by raising and/or lowering pressure andby raising and/or lowering temperature). Examples of the air cyclemachine 190 include a two-wheel, a three-wheel machine, a fourwheel-machine, etc.

The intercooled cooled cooling air system 100 comprises improvements inproviding cooling air from the compressor section 24 to the turbinesection 28 in the gas turbine engine 20. Embodiments of theseimprovements include a cooling-pumping-cooling operation,pumping-cooling-cooling operation, and cooling-cooling-pumpingoperation. An example the cooling-pumping-cooling operation of theintercooled cooled cooling air system 100 will now be described.

In the case where an operating temperature in the turbine section 26 thegas turbine engine 20 is at a high temperature (at or exceeding materiallimits), air can be bled from the first port 145 by the value 150,operated by an actuator, of the intercooled cooled cooling air system100. This air can be referred to as bleed air (e.g., a first bleed airflow). Further, air can be bled from the second port 165 by the value170, operated by an actuator, of the intercooled cooled cooling airsystem 100. This air can also be referred to as bleed air (e.g., asecond bleed air flow). In the example cooling-pumping-coolingoperation, the bleed air that is described as being extracted from thefirst port 145 at the low pressure portion of the compressor section 24to produce low pressure bleed air, and the air that is extracted fromthe second port 145 at the high pressure portion of the compressorsection 24 can be high pressure bleed air. Note that the pressure of theair is generally the same at an exhaust of the compressor section 24 andat an intake of the turbine section 28 because there is a minimal amountof pressure loss when going through the combustor section 26.

The low pressure bleed air from the first port 145 can be supplied tothe staged cooling arrangement of the intercooled cooled cooling airsystem 100. As shown in FIG. 2, the low pressure bleed air passesthrough the first heat exchanger 110, where it is cooled to produce coollow pressure bleed air (cooling). The cool low pressure bleed air isthen supplied to the pump 105, which pressurizes the cool low pressurebleed air to produce cool high pressure bleed air (pumping). The coollow pressure bleed air can also be supplied to the air cycle machine 190(via vale 195), which can receive any percentage or portion of the coollow pressure bleed air. In an embodiment, an inlet of the air cyclemachine 190 can be in fluid communication with bleed air that isupstream of the pump 105 and downstream of the first heat exchanger 210.As shown in FIG. 2, the inlet can be represented as the valve 195, whichselectively regulate the bleed air to the air cycle machine 190.

Next, the cool high pressure bleed air passes through the second heatexchanger 115, where it is further cooled to produce the cooled coolhigh pressure bleed air (cooling). The cool high pressure bleed air canalso be supplied to the air cycle machine 190 (via valve 196), which canreceive any percentage or portion of the cool high pressure bleed air.The cooled cool high pressure bleed air from the staged coolingarrangement can then be mixed at the demarcation point 180 with the highpressure bleed air from the second port 165 to produce intercooledcooled cooling air. In an embodiment, an inlet of the air cycle machine190 can be in fluid communication with bleed air that is upstream of thedemarcation 180 and downstream of the second heat exchanger 210. Asshown in FIG. 2, the inlet can be represented as the valve 196, whichselectively regulate the bleed air to the air cycle machine 190.

The air cycle machine 190 can utilize the received cool low pressurebleed air and/or cool high pressure bleed air respectively received fromthe exhausts of the first heat exchanger 110 and the second heatexchanger 115 to provide pneumatic power to an accessory. By providingthe pneumatic power, the air cycle machine 190 can also producebyproduct of cool/cold air. The air cycle machine 190 is one example ofa device that can receive cool low pressure bleed air and/or cool highpressure bleed air and is not intended to be limiting.

Note that the act of cooling by the first heat exchanger 110 can cause apressure drop on the bleed air. In this way, the first heat exchanger110 can be configured to offset a performance of the pump 105. Further,the pump 105 can be configured to pressurize the air to at, slightlyabove, or considerably above the pressure at the exhaust of thecompressor section 24 to compensate for an original low pressure at thefirst port 145 and/or for the pressure drop across the staged coolingarrangement. Furthermore, the second heat exchanger can be configured tocool the air exhausted from the pump 105 back down.

FIG. 3 is an intercooled cooled cooling air system 200 in accordancewith another embodiment. In general, the intercooled cooled cooling airsystem 200 comprises a staged cooling arrangement located in a bypassduct of the gas turbine engine 20. Components of the intercooled cooledcooling air system 100 and the gas turbine engine 20 that are similar tothe intercooled cooled cooling air system 200 have been reused for easeof explanation, by using the same identifiers, and are notre-introduced. Components of the environmental control system 200comprise a first heat exchanger 210, a second heat exchanger 215, agearbox 220, a bleed port 225, and a fan section 22 comprising aplurality of fans. In a non-limiting embodiment, the fan section 22comprises a first fan 230, a second fan 235, and a third fan 240.Components of the environmental control system 200 also comprise one ormore bypass streams encased by ducts. In an embodiment and as shown inFIG. 3, a main bypass stream 265 (fan 245) and a secondary bypass stream275 (fans 243 and 244) are isolated within first and second bypass ductsof the gas turbine engine 20 (by a first duct wall 276 and a second ductwall 277). A third bypass stream 285 can be located in a third bypassduct external to the second bypass duct, but within a casing of the gasturbine engine 20 (e.g., located in an outer duct that bypasses the fansection 22). The intercooled cooled cooling air system 200 is alsointegrated with a pump 290 and an electric generator 291.

As shown in FIG. 3, the first heat exchanger 210 and the second heatexchanger 215 are aligned in the secondary bypass stream 275 to enablethe stream to act as the heat sink for the bleed air flow from the firstport 145. Within the secondary bypass stream 275, the first heatexchanger 210 is upstream of the second heat exchanger 215. Alternativeembodiments include collectively aligning the first heat exchanger 210and the second heat exchanger 215 in the main bypass stream 265,collectively aligning the first heat exchanger 210 and the second heatexchanger 215 in the third bypass stream 285, collectively aligning thefirst heat exchanger 210 and the second heat exchanger 215 on the firstduct wall 276 (e.g., to enable a combination of streams the main bypassstream 265 and the secondary bypass stream 275), and collectivelyaligning the first heat exchanger 210 and the second heat exchanger 215on the second duct wall 277 (e.g., to enable a combination of streamsthe secondary bypass stream 275 and the third bypass stream 285).Alternative embodiments also include separately aligning the first heatexchanger 210 and the second heat exchanger 215 in different streams275, 285, and 295 and/or on different duct walls 276 and 277. Further,embodiments can include utilizing one or more sources for a heat sink,such as bleed air, fluid cooling, air cycle machine cooling, etc., inlieu of or in addition to the streams described herein.

The pump 290 can selectively receive cool low pressure bleed air and/orcool high pressure bleed air respectively received from the exhausts ofthe first heat exchanger 110 and the second heat exchanger 115regardless of their location. In a non-limiting embodiment, the pump 290can be a turbine. Selective regulation can be implemented by operationsof the valve 195 and the valve 196, which can operate in response tooperating conditions of the gas turbine engine 20 and/or other systems(e.g., an electric heater powered by the generator 291 requires morepower, and therefore a higher percentage or portion of bleed air issupplied by the valve 195 and/or valve 196 to generate that power).Embodiments of selective regulation include the pump 290 receiving bleedair from only the valve 195; the pump 290 receiving bleed air from onlythe valve 196; the pump 290 receiving bleed air from both the valve 195and the valve 196; the pump 290 receiving proportional bleed air fromthe valve 195 and the valve 196; etc.

The pump 290 can extract work from the cool low pressure bleed airand/or the cool high pressure bleed air to provide pneumatic power tothe generator 291. By providing the pneumatic power to the generator291, the generator 291 can produce electricity to power one or moreapplications (see dash-arrow pointing to dashed-circle A). Examples ofapplication include electricity to provide heat to diffuser (e.g.,electric heater); providing thermo-electricity to an auxiliary system;electricity to provide shaft power (e.g., gearbox generator, motordrive, pump, etc.); electricity to provide aircraft power (e.g.,aircraft system); etc. The work extracted by the pump produces byproductof cool/cold air that can be a cooling sink for one or more applicationselsewhere in the gas turbine engine 20 or aircraft (see dash-arrowpointing to dashed-circle B). In an embodiment, the one or moreapplications include providing the cooling sink to an environmentalcontrol system of an aircraft.

Also, as shown in FIG. 3, the gear box 220 can be fluidly coupled tobleed port 225. The gear box 220 can, in turn, be power by extractedfrom bleed air sourced from the bleed port 225 to drive the pump 105(e.g., cause the pump to compress bleed air received from the first heatexchanger 210). In another non-limiting embodiment, the gear box 220 canbe representative of an electric motor that powers the pump 105.

Technical effect and benefits of an intercooled cooled cooling airsystem include producing a cold heat sink and/or cool flow from directcooling, where a two heat exchanger configuration further providesvariable options for the pressure and temperature of the coolingTechnical effect and benefits of an intercooled cooled cooling airsystem include producing a variable speed, variable power off-take to beused on an accessory like generator.

The term “about” is intended to include the degree of error associatedwith measurement of the particular quantity based upon the equipmentavailable at the time of filing the application. For example, “about”can include a range of ±8% or 5%, or 2% of a given value.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,element components, and/or groups thereof.

While the present disclosure has been described with reference to anexemplary embodiment or embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe present disclosure. In addition, many modifications may be made toadapt a particular situation or material to the teachings of the presentdisclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this present disclosure, but that the present disclosurewill include all embodiments falling within the scope of the claims.

The invention claimed is:
 1. A gas turbine engine, comprising: acompressor section; a combustor section; a turbine section; and anintercooled cooling system for the gas turbine engine, the intercooledcooling system comprising: a plurality of heat exchangers in fluidcommunication with an air stream utilized by the plurality of heatexchangers for cooling, wherein a first heat exchanger of the pluralityof heat exchangers is fluidly coupled to a first bleed port of thecompressor section to receive and cool bleed air with the air stream toproduce a cool bleed air; a pump fluidly coupled to the first heatexchanger to receive and increase a pressure of the cool bleed air toproduce a pressurized cool bleed air, wherein a second heat exchanger ofthe plurality of heat exchangers is fluidly coupled to the pump toreceive and cool the pressurized cool bleed air to produce anintercooled cooling air; an air cycle machine in fluid communication tooutputs of the first and second heat exchangers to selectively receiveat least a portion of the cool bleed air or at least a portion of theintercooled cooling air; a first valve configured to selectively providethe cool bleed air to the air cycle machine without passing through thesecond heat exchanger, a second valve configured to selectively providethe intercooled cooling air to the air cycle machine, and a third valveconfigured to selectively provide the intercooled cooling air to theturbine section, wherein said second valve selectively delivers theintercooled cooling air to the air cycle machine and to the third valve,and wherein air delivered from said second valve towards said thirdvalve passes into a mixing chamber, and a second bleed port from saidcompressor section delivers air into said mixing chamber to mix withsaid intercooled cooling air before reaching said third valve.
 2. Thegas turbine engine of claim 1, wherein the first bleed port comprises aport at a low pressure location of the compressor section or a port at amid-pressure location of the compressor section.
 3. The gas turbineengine of claim 1, wherein the first and second heat exchangers arepositioned in a main bypass of the gas turbine engine to receive the airstream.
 4. The gas turbine engine of claim 1, wherein the air cyclemachine comprises an air cycle turbine configured to receive and extractwork from the portion of the cool bleed air or the portion of theintercooled cooling air.
 5. The gas turbine engine of claim 1, whereinthe air cycle turbine produces a byproduct of cold air from theextraction of work from the portion of the cool bleed air or the portionof the intercooled cooling air.
 6. The gas turbine engine of claim 5,wherein the byproduct of cold air is provided as a cooling sink for anenvironmental control system.
 7. The gas turbine engine of claim 1,wherein the air cycle machine comprises a generator coupled to receivepneumatic power from an air cycle turbine.
 8. The gas turbine engine ofclaim 7, wherein the generator provides electricity based on thepneumatic power to one or more of an electric heater, an auxiliarysystem, a motor drive, and an aircraft system.
 9. The gas turbine engineas set forth in claim 1, wherein a fourth valve is positioned betweensaid second bleed port and said mixing chamber to selectively allow orblock flow from said second bleed port to said mixing chamber.